Structure and mechanism of Pseudomonas aeruginosa PA0254/HudA, a prFMNdependent pyrrole-2-carboxylic acid decarboxylase linked to virulence

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Stephen Marshall
  • Karl Fisher
  • Stephen Rigby
  • Reynard Spiess
  • Diego Cannas


The UbiD family of reversible (de)carboxylases depends on the recently discovered prenylated-FMN (prFMN) cofactor for activity. The model enzyme ferulic acid decarboxylase (Fdc1) decarboxylates unsaturated aliphatic acids via a reversible 1,3-cycloaddition process. Protein engineering has extended the Fdc1 substrate range to include (hetero)aromatic acids, although catalytic rates remain poor. This raises the question how efficient decarboxylation of (hetero)aromatic acids is achieved by other UbiD family members. Here we show that the Pseudomonas aeruginosa virulence attenuation factor PA0254/HudA is a pyrrole-2-carboxylic acid decarboxylase. The crystal structure of the enzyme in presence of the reversible inhibitor imidazole reveals a covalent prFMN-imidazole adduct is formed. Substrate screening reveals HudA and selected active site variants can accept a modest range of heteroaromatic compounds, including thiophene-2-carboxylic acid. Together with computational studies, our data suggests prFMN covalent catalysis occurs via electrophilic aromatic substitution and link HudA activity with inhibitory effects of pyrrole-2-carboxylic acid on P. aeruginosa quorum sensing.

Bibliographical metadata

Original languageEnglish
JournalACS Catalysis
Publication statusAccepted/In press - 5 Feb 2021